I want to add lines at beginning of file, it works with:
sed -i '1s/^/#INFO\tFORMAT\tunknown\n/' file
sed -i '1s/^/##phasing=none\n/' file
However it doesn't work when my file is empty. I found these commands:
echo > file && sed '1s/^/#INFO\tFORMAT\tunknown\n/' -i file
echo > file && sed '1s/^/##phasing=none\n/' -i file
but the last one erase the first one (and also if file isn't empty)
I would like to know how to add lines at the beginning of file either if the file is empty or not
I tried a loop with if [ -s file ] but without success
Thanks!
You can use the insert command (i).
if [ -s file ]; then
sed -i '1i\
#INFO\tFORMAT\tunknown\
##phasing=none' file
else
printf '#INFO\tFORMAT\tunknown\n##phasing=none' > file
fi
Note that \t for tab is not POSIX, and does not work on all sed implementations (eg BSD/Apple, -i works differently there too). You can use a raw tab instead, or a variable: tab=$(printf '\t').
You should use i command in sed:
file='inputFile'
# insert a line break if file is empty
[[ ! -s $file ]] && echo > "$file"
sed -i.bak $'1i\
#INFO\tFORMAT\tunknown
' "$file"
Or you can ditch sed and do it in the shell using printf:
{ printf '#INFO\tFORMAT\tunknown\n'; cat file; } > file.new &&
mv file.new file
With plain bash and shell utilities:
#!/bin/bash
header=(
$'#INFO\tFORMAT\tunknown'
$'##phasing=none'
)
mv file file.bak &&
{ printf '%s\n' "${header[#]}"; cat file.bak; } > file &&
rm file.bak
Explicitely creating a new file, then moving it:
#!/bin/bash
echo -e '#INFO\tFORMAT\tunknown' | cat - file > file.new
mv file.new file
or slurping the whole content of the file into memory:
#!/bin/bash
printf '#INFO\tFORMAT\tunknown\n%s' "$(<file)" > file
It is trivial with ed if available/acceptable.
printf '%s\n' '0a' $'#INFO\tFORMAT\tunknown' $'##phasing=none' . ,p w | ed -s file
It even creates the file if it does not exists.
Related
I have a test.txt file with the following contents
100001
100003
100007
100008
100009
I am trying to loop through the text file and append each one with .xml.
Ex:
100001.xml
100003.xml
100007.xml
100008.xml
100009.xml
I have tried different variations of
while read p; do
echo "$p.zip"
done < test.txt
But it prints out weird like this
.xml01
.xml03
.xml07
.xml08
.xml09
Appending a .xml at the end of each line while removing CRLF, if present.
With sed and bash:
#!/bin/bash
sed -E $'s/\r?$/.xml/' test.txt
With awk:
awk -v suffix='.xml' '{sub(/\r?$/,suffix)}1' test.txt
Using it in a bash loop:
#!/bin/bash
while IFS='' read -r filename
do
printf '%q\n' "$filename"
done < <(
awk -v suffix='.xml' '{sub(/\r?$/,suffix)}1' test.txt
)
Or doing the whole thing in pure shell:
while IFS='' read -r filename
do
fullname="${filename%\r}.xml"
printf '%s\n' "$fullname"
done < test.txt
I have a textfile called log.txt, and it logs the file name and the path it was gotten from. so something like this
2.txt
/home/test/etc/2.txt
basically the file name and its previous location. I want to use grep to grab the file directory save it as a variable and move the file back to its original location.
for var in "$#"
do
if grep "$var" log.txt
then
# code if found
else
# code if not found
fi
this just prints out to the console the 2.txt and its directory since the directory has 2.txt in it.
thanks.
Maybe flip the logic to make it more efficient?
f=''
while read prev
do case "$prev" in
*/*) f="${prev##*/}"; continue;; # remember the name
*) [[ -e "$f" ]] && mv "$f" "$prev";;
done < log.txt
That walks through all the files in the log and if they exist locally, move them back. Should be functionally the same without a grep per file.
If the name is always the same then why save it in the log at all?
If it is, then
while read prev
do f="${prev##*/}" # strip the path info
[[ -e "$f" ]] && mv "$f" "$prev"
done < <( grep / log.txt )
Having the file names on the same line would significantly simplify your script. But maybe try something like
# Convert from command-line arguments to lines
printf '%s\n' "$#" |
# Pair up with entries in file
awk 'NR==FNR { f[$0]; next }
FNR%2 { if ($0 in f) p=$0; else p=""; next }
p { print "mv \"" p "\" \"" $0 "\"" }' - log.txt |
sh
Test it by replacing sh with cat and see what you get. If it looks correct, switch back.
Briefly, something similar could perhaps be pulled off with printf '%s\n' "$#" | grep -A 1 -Fxf - log.txt but you end up having to parse the output to pair up the output lines anyway.
Another solution:
for f in `grep -v "/" log.txt`; do
grep "/$f" log.txt | xargs -I{} cp $f {}
done
grep -q (for "quiet") stops the output
I need to change the title on many pdf files. Pdftk works great and I tried to create a bash script (pdftitle) to make it a single pass:
#!/bin/bash
newtitle=$2
pdftk "$1" data_dump output "$1".data.txt;
sed 's/^InfoKey:\sTitle\nInfoValue:\s.*/InfoKey:\sTitle\nInfoValue:'"$newtitle/" "$1".data.txt > "$1".data.fixed.txt;
pdftk "$1" update_info *.data.fixed.txt output "$1".fixed;
mv "$1".fixed "$1";
rm -f ./*.txt
exit;
So on the cli I would enter
$> pdftitle mypdf.pdf "New Title"
The data.txt that pdftk creates has multiple lines, but only two relevant lines are the targets:
...
InfoBegin
InfoKey: Author
InfoValue: Not Me
InfoBegin
InfoKey: Title
InfoValue: Microsoft Word - Old Title.doc
InfoBegin
InfoKey: Creator
InfoValue: PScript5.dll Version 5.2
...
Of which the subsequent line needs to be replaced:
...
InfoKey: Title
InfoValue: Relevant New Title
...
No error messages are produced but the title remains intact. So it seems that sed is having problems here, but I cannot figure out where or how.
Any help will be greatly appreciated.
Here's a refactoring using Awk which assumes pdftk can write to and read from stdin/stdout using - as the pseudo-filename argument.
#!/bin/bash
filename=$1
shift
pdftk "$filename" data_dump output - |
awk -v title="$*" '/^InfoKey: Title/ { t=1 }
t && /^InfoValue:/ { $0 = "InfoValue: " title; t=0 }1' |
pdftk "$filename" update_info - output "$filename".fixed &&
mv "$filaname".fixed "$filename"
The pattern to set a flag variable when you see a pattern and then acting on a subsequent line if that variable is set is a simple and very common Awk idiom.
There is no need for trailing semicolons or an explicit exit at the end.
#tripleee provided the solution to make the bash script work perfectly:
#!/bin/bash
filename=$1
shift
pdftk "$filename" data_dump output |
awk -v title="$#" '/^InfoKey: Title/ { t=1 }
t && /^InfoValue:/ { $0 = "InfoValue: " title; t=0 }1' > data.txt
pdftk "$filename" update_info data.txt output "$filename".fixed &&
mv "$filename".fixed "$filename"
rm ./data.txt
How do I add a string after each line in a file using bash? Can it be done using the sed command, if so how?
If your sed allows in place editing via the -i parameter:
sed -e 's/$/string after each line/' -i filename
If not, you have to make a temporary file:
typeset TMP_FILE=$( mktemp )
touch "${TMP_FILE}"
cp -p filename "${TMP_FILE}"
sed -e 's/$/string after each line/' "${TMP_FILE}" > filename
I prefer echo. using pure bash:
cat file | while read line; do echo ${line}$string; done
I prefer using awk.
If there is only one column, use $0, else replace it with the last column.
One way,
awk '{print $0, "string to append after each line"}' file > new_file
or this,
awk '$0=$0"string to append after each line"' file > new_file
If you have it, the lam (laminate) utility can do it, for example:
$ lam filename -s "string after each line"
Pure POSIX shell and sponge:
suffix=foobar
while read l ; do printf '%s\n' "$l" "${suffix}" ; done < file |
sponge file
xargs and printf:
suffix=foobar
xargs -L 1 printf "%s${suffix}\n" < file | sponge file
Using join:
suffix=foobar
join file file -e "${suffix}" -o 1.1,2.99999 | sponge file
Shell tools using paste, yes, head
& wc:
suffix=foobar
paste file <(yes "${suffix}" | head -$(wc -l < file) ) | sponge file
Note that paste inserts a Tab char before $suffix.
Of course sponge can be replaced with a temp file, afterwards mv'd over the original filename, as with some other answers...
This is just to add on using the echo command to add a string at the end of each line in a file:
cat input-file | while read line; do echo ${line}"string to add" >> output-file; done
Adding >> directs the changes we've made to the output file.
Sed is a little ugly, you could do it elegantly like so:
hendry#i7 tmp$ cat foo
bar
candy
car
hendry#i7 tmp$ for i in `cat foo`; do echo ${i}bar; done
barbar
candybar
carbar
I have several files which all start with this line:
CREATE PROCEDURE **CHANGING_NAME**
I want to be able to pull the name of the procedure and use it to the rename the file. There is content to each file below this first line.
Has anyone done something like this before?
Thanks
Assuming you have all files in one directory :
#!/bin/bash
for i in *.extension :
do
# Assuming 3rd column of the first line is the new name of the file
# And **CHANGING_NAME** doesn't contain any space or meta characters
newname=$(awk 'NR==1 && /PROCEDURE/ {print $3}' "$i")
if [ "$newname" == "" ]; then
echo "There is no PROCEDURE in the first line";
echo "No new name for file $i";
else
mv "$i" "$newname"
fi
done
With a lot of care and pretending that the **CHANGING_NAME** is well-formed:
for file in *.files; do mv -i -- "$file" "$(awk '{print $3; exit}' $file)" ; done
The -i option is to prevent accidental overriding existing files.
This version works with spaces (and many other strange characters except for /):
for file in *.files; do mv -i -- "$file" "$(sed -n '1s/^CREATE\ PROCEDURE\ \(.*\)$/\1/p' $file)"; done
Since I was never great with awk I might suggest:
#! /bin/bash
#
for i in *.extension
do echo $i
newname=$(head -1 "${i}" | cut -d ' ' -f2)
mv -i "${i}" "${newname}"
done
This assumes all files you're looking for have the same extension. If not, and you need the extension, you could use:
#! /bin/bash
#
for i in *
do echo $i
ext="${i##*.}"
newname=$(head -1 "${i}" | cut -d ' ' -f2)
mv -i "${i}" "${newname}"."${ext}"
done
Both assume all the files are in a single directory.
You can try the next:
perl -lanE 'if($.==1&&/PROCEDURE/){close ARGV;say "$ARGV,$F[2]"}' files*
and if satisfied, change it to
perl -lanE 'if($.==1&&/PROCEDURE/){close ARGV;rename $ARGV,$F[2]}' files*
mv myfile `sed '1 s/.*PROCEDURE\s*//' myfile`
(the sed command will delete the text to the left of the word proceeding PROCEDURE regardless of how many spaces on only the first line and print it out the backticks make it execute in place so it is used as the filename to the mv command)
to move them all and add an extension .ext:
ls *.ext | xargs -I {} mv {} `sed '1 s/.*PROCEDURE\s*//' {}`.ext