I was reading the grep source code and found egrep.sh with the below content:
#!#SHELL#
grep=grep
case $0 in
*/*)
dir=${0%/*}
if test -x "$dir/#grep#"; then
PATH=$dir:$PATH
grep=#grep#
fi;;
esac
exec $grep #option# "$#"
I don't seem to understand how #SHELL# #grep# and #option# works or even what they do in the context they are used
Referenced source is located at: http://git.savannah.gnu.org/cgit/grep.git/tree/src/egrep.sh
Based on the comments, I read the Makefile and found that the #something# were placeholders to be substituted with sed as below:
sed -e 's|[#]SHELL#|$(SHELL)|g' \
-e "$$edit_substring" \
-e "s|[#]grep#|$$grep|g" \
-e "s|[#]option#|$$option|g" <$(srcdir)/egrep.sh >$#-t
$(AM_V_at)chmod a=rx $#-t
$(AM_V_at)mv $#-t $#
Related
I have got a question. How should I proceed and make this code print out and execute curl examples that I have on my external file?
How I want it to work is to match the pattern, get text between the patterns (without the pattern) and then execute it.
Is there way to do this?
Thanks for the help.
read -p "Enter a word: " instance
testfile=test.txt
case $instance in
loresipsum)
sed -n '/^loremipsum1/,${p;/^loremipsum2/q}' $testfile \
| while read -r line; do
makingcurlCall=$(eval "$line")
echo "makingcurlCall"
done < $testfile ;;
foobar)
sed -n '/^foobar1/,${p;/^foobar2/q}' $testfile \
| while read -r line; do
makingcurlCall=$(eval "$line")
echo "makingcurlCall"
done < $testfile ;;
*)
printf 'No match for "%s"\n' ":instance"
esac
Text file looks like this
loremipsum1
curl example1
curl example2
curl example3
loremipsum2
foobar1
curl foo
curl bar
curl foo
foobar2
You cannot have the while loop read from both the output of sed and directly from the file. Your current code is ignoring the output from sed and reading directly from the file. Perhaps refactor it like:
#!/bin/sh
instance=${1-loresipsum}
testfile=test.txt
case $instance in
loresipsum) sed -n '/^loremipsum1/,/^loremipsum2/p' "$testfile";;
foobar) sed -n '/^foobar1/,/^foobar2/p' "$testfile";;
*) echo "Error: no match" >&2;;
esac \
| sed -e 1d -e '$d' -e '/^\s*$/d' | while read -r line; do
# makingcurlCall=$(eval "$line")
echo "makingcurlCall: $line"
done
fzf/ripgrep can search an alternate directory from the command line with something like.
rg something ./sompath | fzf
The fzf documentation has a nice little bash script for generating a preview of rg's results that I call with a shell alias and then open the file with vim:
#!/usr/bin/env bash
RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
INITIAL_QUERY="${*:-}"
IFS=: read -ra selected < <(
FZF_DEFAULT_COMMAND="$RG_PREFIX $(printf %q "$INITIAL_QUERY")" \
fzf --ansi \
--color "hl:-1:underline,hl+:-1:underline:reverse" \
--disabled --query "$INITIAL_QUERY" \
--bind "change:reload:sleep 0.1; $RG_PREFIX {q} || true" \
--bind "alt-enter:unbind(change,alt-enter)+change-prompt(2. fzf> )+enable-search+clear-query" \
--prompt '1. ripgrep> ' \
--delimiter : \
--preview "$BAT_CMD --color=always {1} --highlight-line {2}" \
--preview-window 'up,60%,border-bottom,+{2}+3/3,~3'
)
[ -n "${selected[0]}" ] && nvim "${selected[0]}" "+${selected[1]}"
It's very cool and works great. Unfortunately, there's no way to pass in a directory argument into this script. So you have to cd into the desired directory, do the search, and cd back.
Instead, I'd like to do something like this:
search_script initial_query ./some_dir
But my bash skills are weak and I'm not really sure what the best approach is for processing an optional directory argument.
The script has to somehow be smart enough to recognize when a directory argument is passed and when it isn't. I'm not sure if some kind of option string like --dir is the best way to go or what. And I'm wondering if I might be missing something really obvious solution, too.
Thanks.
I was able to cargo cult some little bash snippets and piece something that seems to do the trick and detect if last argument is a directory:
RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
INITIAL_QUERY="${*:-}"
last="${#: -1}"
if [[ -d $last ]]; then
INITIAL_QUERY="${#:1:$#-1}";
dir=$last
echo $INITIAL_QUERY
fi
IFS=: read -ra selected < <(
FZF_DEFAULT_COMMAND="$RG_PREFIX $(printf %q "$INITIAL_QUERY") $dir" \
fzf --ansi \
--color "hl:-1:underline,hl+:-1:underline:reverse" \
--disabled --query "$INITIAL_QUERY" \
--bind "change:reload:sleep 0.1; $RG_PREFIX {q} $dir || true" \
--bind "alt-enter:unbind(change,alt-enter)+change-prompt(2. fzf> )+enable-search+clear-query" \
--prompt '1. ripgrep> ' \
--delimiter : \
--preview "bat --color=always {1} --highlight-line {2}" \
--preview-window 'up,60%,border-bottom,+{2}+3/3,~3'
)
[ -n "${selected[0]}" ] && nvim "${selected[0]}" "+${selected[1]}"
If you think there is a simpler way or a better, I'd love to hear.
At fisrt,I have write the code,and it run well.
# version1
all_num=10
thread_num=5
a=$(date +%H%M%S)
seq 1 ${all_num} | xargs -n 1 -I {} -P ${thread_num} sh -c 'echo abc{}'
b=$(date +%H%M%S)
echo -e "startTime:\t$a"
echo -e "endTime:\t$b"
Now I want to extract code into a funciton,but it was wrong,how to fix it?
get_file(i){
echo "abc"+i
}
all_num=10
thread_num=5
a=$(date +%H%M%S)
seq 1 ${all_num} | xargs -n 1 -I {} -P ${thread_num} sh -c "$(get_file {})"
b=$(date +%H%M%S)
echo -e "startTime:\t$a"
echo -e "endTime:\t$b"
Because /bin/sh isn't guaranteed to have support for either printing text that when evaluates defines your function, or exporting functions through the environment, we need to do this the hard way, just duplicating the text of the function inside the copy of sh started by xargs.
Other questions already exist in this site describing how to accomplish this with bash, which is quite considerably easier. See f/e How can I use xargs to run a function in a command substitution for each match?
#!/bin/sh
all_num=10
thread_num=5
batch_size=1 # but with a larger all_num, turn this up to start fewer copies of sh
a=$(date +%H%M%S) # warning: this is really inefficient
seq 1 ${all_num} | xargs -n "${batch_size}" -P "${thread_num}" sh -c '
get_file() { i=$1; echo "abc ${i}"; }
for arg do
get_file "$arg"
done
' _
b=$(date +%H%M%S)
printf 'startTime:\t%s\n' "$a"
printf 'endTime:\t%s\n' "$b"
Note:
echo -e is not guaranteed to work with /bin/sh. Moreover, for a shell to be truly compliant, echo -e is required to write -e to its output. See Why is printf better than echo? on UNIX & Linux Stack Exchange, and the APPLICATION USAGE section of the POSIX echo specification.
Putting {} in a sh -c '...{}...' position is a Really Bad Idea. Consider the case where you're passed in a filename that contains $(rm -rf ~)'$(rm -rf ~)' -- it can't be safely inserted in an unquoted context, or a double-quoted context, or a single-quoted context, or a heredoc.
Note that seq is also nonstandard and not guaranteed to be present on all POSIX-compliant systems. i=0; while [ "$i" -lt "$all_num" ]; do echo "$i"; i=$((i + 1)); done is an alternative that will work on all POSIX systems.
I am reading configurations from .config file and I want to do some operation if a configuration is enabled. I have written following function but it is throwing error message "/bin/sh: 1: Syntax error: ")" unexpected (expecting "then")"
define parse_configs
while read -r file; do \
config=$$(echo $$file | grep -Po '(?<=(CONFIG_)).*(?==)'); \
val=$$(echo $$file | grep -Po '(?<=(=)).*'); \
$$(if $(findstring y, $$val), echo "do Ops", echo "No ops"); \
done < .config;
endef
The problem is with if statement, other part of function is fine. Please let me know the mistake in the code. Thanks.
What is wrong with the statement:
$$(if $(findstring y, $$val), echo "do Ops", echo "No ops");
is that is actually a GNU Make if-function,
calling the GNU Make findstring-function,
which you have written in the middle of a shell statement, and required ($$) that it be expanded by the shell, but it makes no sense to the shell.
It might as well be Javascript. Replace it with an appropriate shell if-statement, e.g.
while read -r file; do \
config=$$(echo $$file | grep -Po '(?<=(CONFIG_)).*(?==)'); \
val=$$(echo $$file | grep -Po '(?<=(=)).*'); \
if [ -z $${val##*"y"*} ]; then echo "do Ops"; else echo "No ops"; fi; \
done < .config;
I have used the find command for this, but it doesnt return any message when a file is not found.
And I want the search to be recursive and return a message "not found" when a file is not found.
Here's the code I have done so far. Here "input.txt" contains the list of files to be searched.
set `cat input.txt`
echo $#
for i in $#
do
find $HOME -name $i
done
Try this:
listfile=input.txt
exec 3>&1
find | \
grep -f <( sed 's|.*|/&$|' "$listfile" ) | \
tee /dev/fd/3 | \
sed 's|.*/\([^/]*\)$|\1|' | \
grep -v -f - "$listfile" | \
sed 's/$/ Not found/'
exec 3>&-
open file descriptor 3
find the files
see if they're on the list (use sed to
send a copy of the found ones to file descriptor 3
strip off the directory name
get a list of the ones that don't appear
add the "Not found" message
close file descriptor 3
Output looks like:
/path/to/file1
/path/somewhere/file2
foo Not found
bar Not found
No loops necessary.
Whats wrong with using a script. I hope this will do.
#!/bin/bash -f
for i in $#
do
var=`find $HOME -name $i`
if [ -z "$var"]
then
var="File not found"
fi
echo $var
done
You can use the shell builtin 'test' to test the existence of a file. There is also an alternative syntax using square brackets:
if [ -f $a ]; then # Don't forget the semicolon.
echo $a
else
echo 'Not Found'
fi
Here is one way - create a list of all the files to grep against. If your implementation supports
grep -q otherwise use grep [pattern] 2&>1 >/dev/null....
find $HOME -type f |
while read fname
do
echo "$(basename $fname) $fname"
done > /tmp/chk.lis
while read fname
do
grep -q "^$fname" /tmp/chk.lis
[ $? -eq 0 ] && echo "$fname found" || echo "$fname not found"
done < /tmp/chk.lis
All of this is needed because POSIX find does not return an error when a file is not found
perl -nlE'say-f$_?$_:"not found: $_"' file