I have a simple command (my_cc) that computes the number of characters in each line.
This command yields 5, 6, 7, and 8 for text file respectively.
$ cat text
12345
123456
1234567
12345678
$ cat text | ./my_cc
5
6
7
8
My question is how to zip stdin along with stdout line by line like (without multiple processes):
$ cat text | some_magic_command with my_cc
12345 5
123456 6
1234567 7
12345678 8
A possible answer is:
$ cat text | xargs -I {} bash -c "echo {} | ./my_cc | sed 's/^/{} /g'"
12345 5
123456 6
1234567 7
12345678 8
But this invokes processes of my_cc as the number of lines in text.
I can not use this command because my_cc is too heavy to run for each line. Also I can not modify the my_cc.
You can use paste:
paste -d ' ' text <(./my_cc < text)
This puts a space between each line of text and the output of your command.
If you have a shell that doesn't support process substitution, you can read from standard input instead:
./my_cc < text | paste -d ' ' text -
If
my_cc doesn't buffer its output, but writes a line of output immediately after receiving each line of input (most commands don't do that), and
your text doesn't come from a file but is e.g. generated from another command on the fly,
you can do the following:
my_cc() {
perl -nle 'BEGIN { $| = 1 } print length'
}
coproc my_cc
while read -r; do
printf '%s ' "$REPLY"
printf '%s\n' "$REPLY" >&${COPROC[1]}
read -r <&${COPROC[0]}
printf '%s\n' "$REPLY"
done < <( echo '12345
123456
.
1234567
12345678' )
exec {COPROC[0]}<&- {COPROC[1]}>&-
wait $COPROC_PID
Output:
12345 5
123456 6
. 5
1234567 7
12345678 8
Note:
Condition #1 is essential. If my_cc buffers its output, this code will deadlock.
Condition #2 is not strictly required. You could easily run this code on a file (while read -r; do ... done < sometextfile), but a file can be read multiple times, so simpler solutions (that don't require condition #1) are possible.
Explanation:
my_cc is defined as a shell function to stand in for your actual command. It does what you described (prints the length of each line), but $| = 1 deserves comment: This statement enables autoflush mode on the currently selected output handle (which defaults to stdout), i.e. output is written immediately after each print command.
coproc is a bash built-in command that runs the specified command in the background (as a co-process).
The while read -r loop reads input line by line from another command (here played by echo '...').
Each line read ($REPLY) is first printed followed by a space, then sent to the coprocess.
Then we read a single line of output from the coprocess and print it followed by a newline.
At the end we close the file descriptors of our coprocess and wait for it to terminate.
Related
I have a file that holds output from a test.
test 1
42
test 2
69
test 3
420
test 4
55378008
I would like to make the test output appear on the same line as the test name. like so:
test 1: 42
test 2: 69
test 3: 420
test 4: 55378008
I am sure there is some fancy sed, awk or perl way to do this but I am stuck.
And here is another one in sed flavor to complete the offer :
sed 'N ; s/\n/: /' input_file
For each (odd) line starting from the first, append the next (even) one in pattern space separated by a LF, then just replace this LF by :.
awk 'FNR%2{printf "%s: ", $0; next}1' file
This prints odd lines with suffix : and without newline and even lines with a newline.
pr has this built-in, but if you need whitespace adjustment as well, then sed/awk/perl solutions suggested in other answers will suit you better
$ pr -2ats': ' ip.txt
test 1: 42
test 2: 69
test 3: 420
test 4: 55378008
This combines 2 lines at a time with : as the separator.
Just replace the line feed of odd lines with :␠.
perl -pe's/\n/: / if $. % 2'
You have mentioned that you want to removing leading and trailing whitespace as well. For that, you can use the following:
perl -pe's/^\h+|\h+$/g; s/\n/: / if $. % 2'
Specifying file to process to Perl one-liner
A shell solution, which is very slow on large set of data/files.
while IFS= read -r odd_line; do
IFS= read -r even_line
printf '%s: %s\n' "$odd_line" "$even_line"
done < file.txt
On the other hand if the colon is not a requirement paste can do the job.
paste - - < file.txt
Bash solution
skips empty lines
process both UNIX/DOS format 'end of line'
accepts filename as argument or otherwise reads data from STDIN
#!/bin/bash
while read p1
do
[[ -z $p1 ]] && continue
# p1=`echo -n $p1 | tr -d "\r"` # replaced with following line
p1=${p1//$'\r'/}
read p2
echo -n "$p1: $p2"
done < ${1:-/dev/stdin}
Output
test 1: 42
test 2: 69
test 3: 420
test 4: 55378008
NOTE: no empty lines allowed between lines for join
I wish to swap or transpose pairs of lines according to their line-numbers (e.g., switching the positions of lines 10 and 15) in multiple text files using a UNIX tool such as sed or awk.
For example, I believe this sed command should swap lines 14 and 26 in a single file:
sed -n '14p' infile_name > outfile_name
sed -n '26p' infile_name >> outfile_name
How can this be extended to work on multiple files? Any one-liner solutions welcome.
If you want to edit a file, you can use ed, the standard editor. Your task is rather easy in ed:
printf '%s\n' 14m26 26-m14- w q | ed -s file
How does it work?
14m26 tells ed to take line #14 and move it after line #26
26-m14- tells ed to take the line before line #26 (which is your original line #26) and move it after line preceding line #14 (which is where your line #14 originally was)
w tells ed to write the file
q tells ed to quit.
If your numbers are in a variable, you can do:
linea=14
lineb=26
{
printf '%dm%d\n' "$linea" "$lineb"
printf '%d-m%d-\n' "$lineb" "$linea"
printf '%s\n' w q
} | ed -s file
or something similar. Make sure that linea<lineb.
If you want robust in-place updating of your input files, use gniourf_gniourf's excellent ed-based answer
If you have GNU sed and want to in-place updating with multiple files at once, use
#potong's excellent GNU sed-based answer (see below for a portable alternative, and the bottom for an explanation)
Note: ed truly updates the existing file, whereas sed's -i option creates a temporary file behind the scenes, which then replaces the original - while typically not an issue, this can have undesired side effects, most notably, replacing a symlink with a regular file (by contrast, file permissions are correctly preserved).
Below are POSIX-compliant shell functions that wrap both answers.
Stdin/stdout processing, based on #potong's excellent answer:
POSIX sed doesn't support -i for in-place updating.
It also doesn't support using \n inside a character class, so [^\n] must be replaced with a cumbersome workaround that positively defines all character except \n that can occur on a line - this is a achieved with a character class combining printable characters with all (ASCII) control characters other than \n included as literals (via a command substitution using printf).
Also note the need to split the sed script into two -e options, because POSIX sed requires that a branching command (b, in this case) be terminated with either an actual newline or continuation in a separate -e option.
# SYNOPSIS
# swapLines lineNum1 lineNum2
swapLines() {
[ "$1" -ge 1 ] || { printf "ARGUMENT ERROR: Line numbers must be decimal integers >= 1.\n" >&2; return 2; }
[ "$1" -le "$2" ] || { printf "ARGUMENT ERROR: The first line number ($1) must be <= the second ($2).\n" >&2; return 2; }
sed -e "$1"','"$2"'!b' -e ''"$1"'h;'"$1"'!H;'"$2"'!d;x;s/^\([[:print:]'"$(printf '\001\002\003\004\005\006\007\010\011\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037\177')"']*\)\(.*\n\)\(.*\)/\3\2\1/'
}
Example:
$ printf 'line 1\nline 2\nline 3\n' | swapLines 1 3
line 3
line 2
line 1
In-place updating, based on gniourf_gniourf's excellent answer:
Small caveats:
While ed is a POSIX utility, it doesn't come preinstalled on all platforms, notably not on Debian and the Cygwin and MSYS Unix-emulation environments for Windows.
ed always reads the input file as a whole into memory.
# SYNOPSIS
# swapFileLines lineNum1 lineNum2 file
swapFileLines() {
[ "$1" -ge 1 ] || { printf "ARGUMENT ERROR: Line numbers must be decimal integers >= 1.\n" >&2; return 2; }
[ "$1" -le "$2" ] || { printf "ARGUMENT ERROR: The first line number ($1) must be <= the second ($2).\n" >&2; return 2; }
ed -s "$3" <<EOF
H
$1m$2
$2-m$1-
w
EOF
}
Example:
$ printf 'line 1\nline 2\nline 3\n' > file
$ swapFileLines 1 3 file
$ cat file
line 3
line 2
line 1
An explanation of #potong's GNU sed-based answer:
His command swaps lines 10 and 15:
sed -ri '10,15!b;10h;10!H;15!d;x;s/^([^\n]*)(.*\n)(.*)/\3\2\1/' f1 f2 fn
-r activates support for extended regular expressions; here, notably, it allows use of unescaped parentheses to form capture groups.
-i specifies that the files specified as operands (f1, f2, fn) be updated in place, without backup, since no optional suffix for a backup file is adjoined to the -i option.
10,15!b means that all lines that do not (!) fall into the range of lines 10 through 15 should branch (b) implicitly to the end of the script (given that no target-label name follows b), which means that the following commands are skipped for these lines. Effectively, they are simply printed as is.
10h copies (h) line number 10 (the start of the range) to the so-called hold space, which is an auxiliary buffer.
10!H appends (H) every line that is not line 10 - which in this case implies lines 11 through 15 - to the hold space.
15!d deletes (d) every line that is not line 15 (here, lines 10 through 14) and branches to the end of the script (skips remaining commands). By deleting these lines, they are not printed.
x, which is executed only for line 15 (the end of the range), replaces the so-called pattern space with the contents of the hold space, which at that point holds all lines in the range (10 through 15); the pattern space is the buffer on which sed commands operate, and whose contents are printed by default (unless -n was specified).
s/^([^\n]*)(.*\n)(.*)/\3\2\1/ then uses capture groups (parenthesized subexpressions of the regular expression that forms the first argument passed to function s) to partition the contents of the pattern space into the 1st line (^([^\n]*)), the middle lines ((.*\n)), and the last line ((.*)), and then, in the replacement string (the second argument passed to function s), uses backreferences to place the last line (\3) before the middle lines (\2), followed by the first line (\1), effectively swapping the first and last lines in the range. Finally, the modified pattern space is printed.
As you can see, only the range of lines spanning the two lines to swap is held in memory, whereas all other lines are passed through individually, which makes this approach memory-efficient.
This might work for you (GNU sed):
sed -ri '10,15!b;10h;10!H;15!d;x;s/^([^\n]*)(.*\n)(.*)/\3\2\1/' f1 f2 fn
This stores a range of lines in the hold space and then swaps the first and last lines following the completion of the range.
The i flag edits each file (f1,f2 ... fn) in place.
With GNU awk:
awk '
FNR==NR {if(FNR==14) x=$0;if(FNR==26) y=$0;next}
FNR==14 {$0=y} FNR==26 {$0=x} {print}
' file file > file_with_swap
The use of the following helper script allows using the power of find ... -exec ./script '{}' l1 l2 \; to locate the target files and to swap lines l1 & l2 in each file in place. (it requires that there are no identical duplicate lines within the file that fall within the search range) The script uses sed to read the two swap lines from each file into an indexed array and passes the lines to sed to complete the swap by matching. The sed call uses its "matched first address" state to limit the second expression swap to the first occurrence. An example use of the helper script below to swap lines 5 & 15 in all matching files is:
find . -maxdepth 1 -type f -name "lnum*" -exec ../swaplines.sh '{}' 5 15 \;
For example, the find call above found files lnumorig.txt and lnumfile.txt in the present directory originally containing:
$ head -n20 lnumfile.txt.bak
1 A simple line of test in a text file.
2 A simple line of test in a text file.
3 A simple line of test in a text file.
4 A simple line of test in a text file.
5 A simple line of test in a text file.
6 A simple line of test in a text file.
<snip>
14 A simple line of test in a text file.
15 A simple line of test in a text file.
16 A simple line of test in a text file.
17 A simple line of test in a text file.
18 A simple line of test in a text file.
19 A simple line of test in a text file.
20 A simple line of test in a text file.
And swapped the lines 5 & 15 as intended:
$ head -n20 lnumfile.txt
1 A simple line of test in a text file.
2 A simple line of test in a text file.
3 A simple line of test in a text file.
4 A simple line of test in a text file.
15 A simple line of test in a text file.
6 A simple line of test in a text file.
<snip>
14 A simple line of test in a text file.
5 A simple line of test in a text file.
16 A simple line of test in a text file.
17 A simple line of test in a text file.
18 A simple line of test in a text file.
19 A simple line of test in a text file.
20 A simple line of test in a text file.
The helper script itself is:
#!/bin/bash
[ -z $1 ] && { # validate requierd input (defaults set below)
printf "error: insufficient input calling '%s'. usage: file [line1 line2]\n" "${0//*\//}" 1>&2
exit 1
}
l1=${2:-10} # default/initialize line numbers to swap
l2=${3:-15}
while IFS=$'\n' read -r line; do # read lines to swap into indexed array
a+=( "$line" );
done <<<"$(sed -n $((l1))p "$1" && sed -n $((l2))p "$1")"
((${#a[#]} < 2)) && { # validate 2 lines read
printf "error: requested lines '%d & %d' not found in file '%s'\n" $l1 $l2 "$1"
exit 1
}
# swap lines in place with sed (remove .bak for no backups)
sed -i.bak -e "s/${a[1]}/${a[0]}/" -e "0,/${a[0]}/s/${a[0]}/${a[1]}/" "$1"
exit 0
Even though I didn't manage to get it all done in a one-liner I decided it was worth posting in case you can make some use of it or take ideas from it. Note: if you do make use of it, test to your satisfaction before turning it loose on your system. The script currently uses sed -i.bak ... to create backups of the files changed for testing purposes. You can remove the .bak when you are satisfied it meets your needs.
If you have no use for setting default lines to swap in the helper script itself, then I would change the first validation check to [ -z $1 -o -z $2 -o $3 ] to insure all required arguments are given when the script is called.
While it does identify the lines to be swapped by number, it relies on the direct match of each line to accomplish the swap. This means that any identical duplicate lines up to the end of the swap range will cause an unintended match and failue to swap the intended lines. This is part of the limitation imposed by not storing each line within the range of lines to be swapped as discussed in the comments. It's a tradeoff. There are many, many ways to approach this, all will have their benefits and drawbacks. Let me know if you have any questions.
Brute Force Method
Per your comment, I revised the helper script to use the brute forth copy/swap method that would eliminate the problem of any duplicate lines in the search range. This helper obtains the lines via sed as in the original, but then reads all lines from file to tmpfile swapping the appropriately numbered lines when encountered. After the tmpfile is filled, it is copied to the original file and tmpfile is removed.
#!/bin/bash
[ -z $1 ] && { # validate requierd input (defaults set below)
printf "error: insufficient input calling '%s'. usage: file [line1 line2]\n" "${0//*\//}" 1>&2
exit 1
}
l1=${2:-10} # default/initialize line numbers to swap
l2=${3:-15}
while IFS=$'\n' read -r line; do # read lines to swap into indexed array
a+=( "$line" );
done <<<"$(sed -n $((l1))p "$1" && sed -n $((l2))p "$1")"
((${#a[#]} < 2)) && { # validate 2 lines read
printf "error: requested lines '%d & %d' not found in file '%s'\n" $l1 $l2 "$1"
exit 1
}
# create tmpfile, set trap, truncate
fn="$1"
rmtemp () { cp "$tmpfn" "$fn"; rm -f "$tmpfn"; }
trap rmtemp SIGTERM SIGINT EXIT
declare -i n=1
tmpfn="$(mktemp swap_XXX)"
:> "$tmpfn"
# swap lines in place with a tmpfile
while IFS=$'\n' read -r line; do
if ((n == l1)); then
printf "%s\n" "${a[1]}" >> "$tmpfn"
elif ((n == l2)); then
printf "%s\n" "${a[0]}" >> "$tmpfn"
else
printf "%s\n" "$line" >> "$tmpfn"
fi
((n++))
done < "$fn"
exit 0
If the line numbers to be swapped are fixed then you might want to try something like the sed command in the following example to have lines swapped in multiple files in-place:
#!/bin/bash
# prep test files
for f in a b c ; do
( for i in {1..30} ; do echo $f$i ; done ) > /tmp/$f
done
sed -i -s -e '14 {h;d}' -e '15 {N;N;N;N;N;N;N;N;N;N;G;x;d}' -e '26 G' /tmp/{a,b,c}
# -i: inplace editing
# -s: treat each input file separately
# 14 {h;d} # first swap line: hold ; suppress
# 15 {N;N;...;G;x;d} # lines between: collect, append held line; hold result; suppress
# 26 G # second swap line: append held lines (and output them all)
# dump test files
cat /tmp/{a,b,c}
(This is according to Etan Reisner's comment.)
If you want to swap two lines, you can send it through twice, you could make it loop in one sed script if you really wanted, but this works:
e.g.
test.txt: for a in {1..10}; do echo "this is line $a"; done >> test.txt
this is line 1
this is line 2
this is line 3
this is line 4
this is line 5
this is line 6
this is line 7
this is line 8
this is line 9
this is line 10
Then to swap lines 6 and 9:
sed ':a;6,8{6h;6!H;d;ba};9{p;x};' test.txt | sed '7{h;d};9{p;x}'
this is line 1
this is line 2
this is line 3
this is line 4
this is line 5
this is line 9
this is line 7
this is line 8
this is line 6
this is line 10
In the first sed it builds up the hold space with lines 6 through 8.
At line 9 it prints line 9 then prints the hold space (lines 6 through 8) this accomplishes the first move of 9 to place 6. Note: 6h; 6!H avoids a new line at the top of the pattern space.
The second move occurs in the second sed script it saves line 7 to the hold space, then deletes it and prints it after line 9.
To make it quasi-generic you can use variables like this:
A=3 && B=7 && sed ':a;'${A}','$((${B}-1))'{'${A}'h;'${A}'!H;d;ba};'${B}'{p;x};' test.txt | sed $(($A+1))'{h;d};'${B}'{p;x}'
Where A and B are the lines you want to swap, in this case lines 3 and 7.
if, you want swap two lines, to create script "swap.sh"
#!/bin/sh
sed -n "1,$((${2}-1))p" "$1"
sed -n "${3}p" "$1"
sed -n "$((${2}+1)),$((${3}-1))p" "$1"
sed -n "${2}p" "$1"
sed -n "$((${3}+1)),\$p" "$1"
next
sh swap.sh infile_name 14 26 > outfile_name
I have two programs that produce data on stdout, and I'd like to paste their output together. I can successfully do this like so:
paste <(./prog1) <(./prog2)
But I find that this method will print all lines from both inputs,
and what I really want is to stop paste after either input program is finished.
So if ./prog1 produces the output:
a
b
c
But ./prog2 produces:
Hello
World
I would expect the output:
a Hello
b World
Also note that one of the input programs may actually produce infinite output, and I want to be able to handle that case as well. For example, if my inputs are yes and ./prog2, I should get:
y Hello
y World
Use join instead, with a variation on the Schwartzian transform:
numbered () {
nl -s- -ba -nrz
}
join -j 1 <(prog1 | numbered) <(prog2 | numbered) | sed 's/^[^-]*-//'
Piping to nl numbers each line, and join -1 1 will join corresponding lines with the same number. The extra lines in the longer file will have no join partner and be omitted. Once the join is complete, pipe through sed to remove the line numbers.
Here's one solution:
while IFS= read -r -u7 a && IFS= read -r -u8 b; do echo "$a $b"; done 7<$file1 8<$file2
This has the slightly annoying effect of ignoring the last line of an input file if it is not terminated with a newline (but such a file is not a valid text file).
You can wrap this in a function, of course:
paste_short() {
(
while IFS= read -r -u7 a && IFS= read -r -u8 b; do
echo "$a $b"
done
) 7<"$1" 8<"$2"
}
Consider using awk:
awk 'FNR==NR{a[++i]=$0;next} FNR>i{exit}
{print a[FNR], $0}' <(printf "hello\nworld\n") <(printf "a\nb\nc\n")
hello a
world b
Keep the longer output producing program as your 2nd input.
How to I concatenate stdin to a string, like this?
echo "input" | COMMAND "string"
and get
inputstring
A bit hacky, but this might be the shortest way to do what you asked in the question (use a pipe to accept stdout from echo "input" as stdin to another process / command:
echo "input" | awk '{print $1"string"}'
Output:
inputstring
What task are you exactly trying to accomplish? More context can get you more direction on a better solution.
Update - responding to comment:
#NoamRoss
The more idiomatic way of doing what you want is then:
echo 'http://dx.doi.org/'"$(pbpaste)"
The $(...) syntax is called command substitution. In short, it executes the commands enclosed in a new subshell, and substitutes the its stdout output to where the $(...) was invoked in the parent shell. So you would get, in effect:
echo 'http://dx.doi.org/'"rsif.2012.0125"
use cat - to read from stdin, and put it in $() to throw away the trailing newline
echo input | COMMAND "$(cat -)string"
However why don't you drop the pipe and grab the output of the left side in a command substitution:
COMMAND "$(echo input)string"
I'm often using pipes, so this tends to be an easy way to prefix and suffix stdin:
echo -n "my standard in" | cat <(echo -n "prefix... ") - <(echo " ...suffix")
prefix... my standard in ...suffix
There are some ways of accomplish this, i personally think the best is:
echo input | while read line; do echo $line string; done
Another can be by substituting "$" (end of line character) with "string" in a sed command:
echo input | sed "s/$/ string/g"
Why i prefer the former? Because it concatenates a string to stdin instantly, for example with the following command:
(echo input_one ;sleep 5; echo input_two ) | while read line; do echo $line string; done
you get immediatly the first output:
input_one string
and then after 5 seconds you get the other echo:
input_two string
On the other hand using "sed" first it performs all the content of the parenthesis and then it gives it to "sed", so the command
(echo input_one ;sleep 5; echo input_two ) | sed "s/$/ string/g"
will output both the lines
input_one string
input_two string
after 5 seconds.
This can be very useful in cases you are performing calls to functions which takes a long time to complete and want to be continuously updated about the output of the function.
You can do it with sed:
seq 5 | sed '$a\6'
seq 5 | sed '$ s/.*/\0 6/'
In your example:
echo input | sed 's/.*/\0string/'
I know this is a few years late, but you can accomplish this with the xargs -J option:
echo "input" | xargs -J "%" echo "%" "string"
And since it is xargs, you can do this on multiple lines of a file at once. If the file 'names' has three lines, like:
Adam
Bob
Charlie
You could do:
cat names | xargs -n 1 -J "%" echo "I like" "%" "because he is nice"
Also works:
seq -w 0 100 | xargs -I {} echo "string "{}
Will generate strings like:
string 000
string 001
string 002
string 003
string 004
...
The command you posted would take the string "input" use it as COMMAND's stdin stream, which would not produce the results you are looking for unless COMMAND first printed out the contents of its stdin and then printed out its command line arguments.
It seems like what you want to do is more close to command substitution.
http://www.gnu.org/software/bash/manual/html_node/Command-Substitution.html#Command-Substitution
With command substitution you can have a commandline like this:
echo input `COMMAND "string"`
This will first evaluate COMMAND with "string" as input, and then expand the results of that commands execution onto a line, replacing what's between the ‘`’ characters.
cat will be my choice: ls | cat - <(echo new line)
With perl
echo "input" | perl -ne 'print "prefix $_"'
Output:
prefix input
A solution using sd (basically a modern sed; much easier to use IMO):
# replace '$' (end of string marker) with 'Ipsum'
# the `e` flag disables multi-line matching (treats all lines as one)
$ echo "Lorem" | sd --flags e '$' 'Ipsum'
Lorem
Ipsum#no new line here
You might observe that Ipsum appears on a new line, and the output is missing a \n. The reason is echo's output ends in a \n, and you didn't tell sd to add a new \n. sd is technically correct because it's doing exactly what you are asking it to do and nothing else.
However this may not be what you want, so instead you can do this:
# replace '\n$' (new line, immediately followed by end of string) by 'Ipsum\n'
# don't forget to re-add the `\n` that you removed (if you want it)
$ echo "Lorem" | sd --flags e '\n$' 'Ipsum\n'
LoremIpsum
If you have a multi-line string, but you want to append to the end of each individual line:
$ ls
foo bar baz
$ ls | sd '\n' '/file\n'
bar/file
baz/file
foo/file
I want to prepend my sql script with "set" statement before running it.
So I echo the "set" instruction, then pipe it to cat. Command cat takes two parameters : STDIN marked as "-" and my sql file, cat joins both of them to one output. Next I pass the result to mysql command to run it as a script.
echo "set #ZERO_PRODUCTS_DISPLAY='$ZERO_PRODUCTS_DISPLAY';" | cat - sql/test_parameter.sql | mysql
p.s. mysql login and password stored in .my.cnf file
I have two separate text files, one with 4 letter words and one with 4 digit numbers, all on individual lines. The words in the on file correspond to the numbers on the same line in the other file. For example:
CATS
RATS
HATS
matches up with
2287
7287
4287
What I would like is to append the numbers to the end of their matching word, so it looks like this:
CATS2287
RATS7287
HATS4287
so far what I have is this:
for i in $(cat numbers); do
sed 's/$/'$i'/' words;
done
but the problem is a) that doesn't print/echo out to a new file and b) it loops through each word every time the first loop comes to a new number so in the end, all the words are paired up with the last number in the number file. Thanks in advance for the help.
paste -d "" /path/to/letters /path/to/numbers
Proof of Concept
$ paste -d "" CATS NUMS
CATS2287
RATS7287
HATS4287
You can use the excellent little paste(1) utility:
$ cat a
CATS
RATS
HATS
$ cat b
2287
7287
4287
$ paste -d "" a b
CATS2287
RATS7287
HATS4287
$
-d specifies a list of delimiters; I gave it a blank list: no delimiters, no delimiters.
Hmm, my version of paste with -d"" just results in numbers, the words get overwritten (GNU paste 8.10 on cygwin). my input files have no carriage returns.
paste words numbers | tr -d '\t'
Also, just with shell builtins
exec 3<words
exec 4<numbers
while read -u3 word; do
read -u4 num
echo $word$num
done
exec 3<&-
exec 4<&-
On Mac OS X:
paste -d "\0" <(echo abc) <(echo def)
there are a few ways to do that
Paste:
paste -d "" file1 file2
awk
awk '{ getline f<"file2" ; print $0f}' file1
Bash:
exec 6<"file2"
while read -r line
do
read -r S <&6
printf "${line}${S}\n"
done <"file1"
exec >&6-
Ruby(1.9+)
ruby -ne 'BEGIN{f=File.open("file1")};print $_.chomp+f.readline;END{f.close}' file