Basic logging commands for Linux shell scripts
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/bin/bash | |
## | |
## Simple logging mechanism for Bash | |
## | |
## Author: Michael Wayne Goodman <goodman.m.w@gmail.com> | |
## Thanks: Jul for the idea to add a datestring. See: | |
## http://www.goodmami.org/2011/07/simple-logging-in-bash-scripts/#comment-5854 | |
## Thanks: @gffhcks for noting that inf() and debug() should be swapped, | |
## and that critical() used $2 instead of $1 | |
## | |
## License: Public domain; do as you wish | |
## | |
exec 3>&2 # logging stream (file descriptor 3) defaults to STDERR | |
verbosity=3 # default to show warnings | |
silent_lvl=0 | |
crt_lvl=1 | |
err_lvl=2 | |
wrn_lvl=3 | |
inf_lvl=4 | |
dbg_lvl=5 | |
notify() { log $silent_lvl "NOTE: $1"; } # Always prints | |
critical() { log $crt_lvl "CRITICAL: $1"; } | |
error() { log $err_lvl "ERROR: $1"; } | |
warn() { log $wrn_lvl "WARNING: $1"; } | |
inf() { log $inf_lvl "INFO: $1"; } # "info" is already a command | |
debug() { log $dbg_lvl "DEBUG: $1"; } | |
log() { | |
if [ $verbosity -ge $1 ]; then | |
datestring=`date +'%Y-%m-%d %H:%M:%S'` | |
# Expand escaped characters, wrap at 70 chars, indent wrapped lines | |
echo -e "$datestring $2" | fold -w70 -s | sed '2~1s/^/ /' >&3 | |
fi | |
} |
@MapleLove2014, that indents the wrapped lines. 2~1
means to perform the following operation on every line starting from the 2nd (every 1 line after line 2), then s/^/ /
is a substitution operation that matches the beginning of each line (^
) and inserts two spaces. In a terminal you might try man sed
to get more info about the command.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Hello, what does this statement means:
sed '2~1s/^/ /'
?