File me Issues or star this repo.
See more CheatSheets from Denny: #denny-cheatsheets
| Name | Comment |
|---|
| Redirect stdout/stderr | ls /tmp >/dev/null 2>&1 |
| Deal with filename | basename $f, dirname $f |
| Use timeout: avoid command hang | timeout 10 sh -c ‘ls -lt’ |
| Restart shell without killing terminal | exec -l $SHELL |
| Run sub-shell | echo $BASH_SUBSHELL; ( echo "Running in subshell: $BASH_SUBSHELL" ) |
| Run static code check | link: shellcheck |
| Name | Comment |
|---|
| Show file content | cat /etc/hosts |
| Show file content with line numbers | cat -n /etc/hosts |
| Show with line numbers, while excluding blank lines | cat -b /etc/hosts |
| Show the first 3 lines | head -n3 /etc/hosts |
| Show the last 3 lines | tail -n3 /etc/hosts |
| Keep tailing log files | tail -f /var/log/system.log, taif /var/log/system.log |
| Show the 4th line | sed -n '4p' /etc/hosts |
| Show 4th, 5th, 7th and 8th lines | sed -n '4,5p;7,8p' /etc/hosts |
| Show matched string with 3 lines before and after | grep -C 3 "127.0.0.1" /etc/hosts |
| For table-like files, show 2nd column | awk -F'\t' '{print $2}' /etc/hosts |
| For table-like files, swap 1st and 2nd columns | awk -F'\t' '{print $2,$1}' /etc/hosts |
| Name | Comment |
|---|
| Echo red text | echo -e “hello,\e[0;31m there \e[0;31m” |
| Echo multiple lines | echo -e “hello,\ndenny” |
| Echo bold text | echo -e hello, “\033[1mThis is bold text.\033[0m” |
| Echo underlined text | echo -e hello, “\033[4mThis is underlined text.\033[0m” |
1.2.3 Check process via /proc
| Name | Comment |
|---|
| Check process start command | cat /proc/$pid/cmdline |
| Check process environment variables | cat /proc/$pid/environ |
| Check process ulimits setting | cat /proc/$pid/limits |
| Name | Comment |
|---|
| Copy one file | cp /etc/hosts /tmp/hosts |
| Copy one folder | cp -r /usr/local/bin/ /tmp/bin/ |
| Copy for backup | cp /tmp/hosts{,.bak}, ls -lth /tmp/hosts* |
| Name | Comment |
|---|
| Go to given folder | cd /var/log/ |
| Go to home | cd |
| Go to parent folder | cd .. |
| Go to previous folder | cd - |
| Name | Comment |
|---|
| * | expr 5 \* 4 |
| + | let z=x+y, z=$x+$y |
| == | int1 -eq int2, =[ $? -eq 0 ] && echo “good”= |
| >= | int1 -ge =int2 |
| > | int1 -gt =int2 |
| <= | int1 -le =int2 |
| < | int1 -lt =int2 |
| != | int1 -ne =int2 |
# Run grep for files filtered by find
find /var/log -name "*.log" | xargs grep -i error
# Loop with pipes
cat /etc/passwd | awk -F':' '{print $1}' | xargs -I{} sudo -l -U {} | grep -v "not allowed to"[ 0 -eq $(find ./data -name "*.txt" -type f -print | wc -l) ]
/sbin/ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}'
- Check if a string contains a substring
#!/bin/bash
S="Pineapple"
if [[ "${S}" == *apple* ]]; then
echo "Yes"
else
echo "No"
fi
- Check if a string in a list
stackoverflow link
#!/usr/bin/env bash
IAAS_TYPE="gcp|aws"
TYPE="gcp"
if [[ "gcp|aws" == *${TYPE}* ]]; then
echo "yes"
else
echo "no"
fiLicense: Code is licensed under MIT License.
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