If it was the exit code and not the result, you could just use if func arg; then … If you cannot make the function return a proper exit code (with return N), and you have to use string results, use Alex Gitelman’s answer. $ help if: if: if COMMANDS; then COMMANDS; [ elif COMMANDS; … Read more
Pure Bash, no external utilities This demonstration does full justification, but you can just omit subtracting the length of the second string if you want ragged-right lines. pad=$(printf ‘%0.1s’ “-“{1..60}) padlength=40 string2=’bbbbbbb’ for string1 in a aa aaaa aaaaaaaa do printf ‘%s’ “$string1” printf ‘%*.*s’ 0 $((padlength – ${#string1} – ${#string2} )) “$pad” printf ‘%s\n’ … Read more
sending the signal 0 to a given PID just checks if any process with the given PID is running and you have the permission to send a signal to it. For more information see the following manpages: kill(1) $ man 1 kill … If sig is 0, then no signal is sent, but error checking … Read more
You can use the -i flag which makes your pattern case insensitive: grep -iF “success…” file1 Also, there is no need for cat. grep takes a file with the syntax grep <pattern> <file>. I also used the -F flag to search for a fixed string to avoid escaping the ellipsis.
To view all env variables: docker exec container env To get one: docker exec container env | grep VARIABLE | cut -d’=’ -f2
Try this Bash syntax instead of trying to use an external program expr: count=$((FIRSTV-SECONDV)) BTW, the correct syntax of using expr is: count=$(expr $FIRSTV – $SECONDV) But keep in mind using expr is going to be slower than the internal Bash syntax I provided above.
“Permission denied” prevents your script from being invoked at all. Thus, the only syntax that could be possibly pertinent is that of the first line (the “shebang”), which should look like #!/usr/bin/env bash, or #!/bin/bash, or similar depending on your target’s filesystem layout. Most likely the filesystem permissions not being set to allow execute. It’s … Read more
I think all you’re looking for is to read multiple variables per line: the read command can assign words to variables by itself. while read -r first second third; do do_stuff_with “$first” do_stuff_with “$second” do_stuff_with “$third” done < ./test.txt
Well… command is likely built in to your shell, and with the -v option will tell you how your shell will invoke the command specified as its option. which is an external binary, located at /usr/bin/which which steps through the $PATH environment variable and checks for the existence of a file. A reason to select … Read more
You have to reset all arguments. To change e.g. argument $3: $ set — “${@:1:2}” “new_arg3” “${@:4}” Basically you set all arguments to their current values, except for the one(s) that you want to change. set — is also specified by POSIX 7. The “${@:1:2}” notation is expanded to the two (hence the 2 in … Read more