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Commands using expr from sorted by
Terminal - Commands using expr - 16 results
if [[ $(expr $(date +%s) - $(stat -c %X /var/lib/apt/periodic/update-success-stamp)) -gt 86400 ]]; then sudo apt-get update fi
2015-05-12 14:45:11
User: gargolito
Functions: date expr stat sudo

I have this in my .bash_aliases and call it before running apt-get install or apt-get upgrade


alias apt-install='apt-update; apt-get install'

alias apt-upgrade='apt-update; apt-get upgrade'

function apt-update () {

if [[ $(expr $(date +%s) - $(stat -c %X /var/lib/apt/periodic/update-success-stamp)) -gt 86400 ]]; then

sudo apt-get update


echo apt is up to date



while ( true ) ; do if [ $(expr $RANDOM % 2 ) -eq 0 ] ; then echo -ne "\xE2\x95\xB1" ; else echo -ne "\xE2\x95\xB2" ; fi ; done
2015-01-17 12:46:37
User: tobi
Functions: echo expr true

Generates labyrinth-like pattern on UTF-8 terminal in bash.

For fun ;)

port=32768; while netstat -atn | grep -q :$port; do port=$(expr $port + 1); done; echo $port
expr `echo "123671" | sed -e 's/[0-9]/ + &/g' -e 's/^ +//g'` 20
dd of=output.txt if=input.txt ibs=1 skip=$(expr `stat -c%s input.txt` / 2)
i=0;while :; do i=$(expr "$i" + 1); scrot "$i".png; sleep 2; done;
2011-05-27 00:25:28
User: scripteles
Functions: expr sleep

Take a screenshot every 2 seconds and save it as a png file

expr `find . -type f -printf "%s + "0`
fname=$1;f=$(ls -la $fname);fsz=$(echo $f|awk '{ print $5 }');nrrec=$(wc -l $fname|awk '{ print $1 }');recsz=$(expr $fsz / $nrrec);echo "$recsz"
2010-09-14 08:40:22
User: vuurst
Functions: awk echo expr ls wc

command was too long...

this is the complete command:

fname=$1; f=$( ls -la $fname ); if [ -n "$f" ]; then fsz=$( echo $f | awk '{ print $5 }' ); if [ "$fsz" -ne "0" ]; then nrrec=$( wc -l $fname | awk '{ print $1 }' ); recsz=$( expr $fsz / $nrrec ); echo "$recsz"; else echo "0"; fi else echo "file $fname does not exist" >&2; fi

First the input is stored in var $fname

The file is checked for existance using "ls -lart".

If the output of "ls -lart" is empty, the error message is given on stderr

Otherwise the filelength is taken from the output of "ls -lart" (5th field)

With "wc -l" the number of records (or lines) is taken.

The record size is filelength devided by the number of records.

please note: this method does not take into account any headers, variable length records and only works on ascii files where the records are sperated by 0x0A (or 0x0A/0x0D on MS-DOS/Windows).

jb() { if [ -z $1 ];then printf 'usage:\njb <"date and/or time"> <"commandline"> &\nsee parsedate(3) strftime(3)\n';else t1=$(date +%s); t2=$(date -d "$1" +%s) ;sleep $(expr $t2 - $t1);$2 ;fi ;}
2010-08-26 23:50:42
User: argv
Functions: date expr printf


jb "next sun 12pm" "/bin/sh ~you/1.sh" &

jb "2010-08-29 12:00:00" "~you/1.sh" &

jb "29aug2010 gmt" ". ~you/1.sh" &

jb 12:00p.m. "nohup ./1.sh" &

jb 1min "echo stop!" &


parsedate(3) strftime(3)

watch -tn1 'date -u +%T -d @$(expr $(date -d HH:MM +%s) - $(date +%s)) | toilet -f bigmono12'
2010-06-26 11:56:11
User: prayer
Functions: date expr watch
Tags: date time

Change HH:MM with your target time.

This is for a Debian/Ubuntu GNU system. You need bash (package bash), date (package coreutils) and toilet (package toilet). Install with:

# apt-get install bash coreutils toilet toilet-fonts

while [ 1 -lt 2 ]; do i=0; COL=$((RANDOM%$(tput cols)));ROW=$((RANDOM%$(tput cols)));while [ $i -lt $COL ]; do tput cup $i $ROW;echo -e "\033[1;34m" $(cat /dev/urandom | head -1 | cut -c1-1) 2>/dev/null ; i=$(expr $i + 1); done; done
2010-05-28 16:07:56
User: dave1010
Functions: cat cut expr head tput

Same as original, but works in bash

while :; do integer i=0; COL=$((RANDOM%$(tput cols))); ROW=$((RANDOM%$(tput cols))); while (( i <= COL)) do tput cup $i $ROW; echo "\033[1;34m" $(cat /dev/urandom | head -1 | cut -c1-1) 2>/dev/null; i=$(expr $i + 1); done done
a=($(ls *html)) && a=${a[$(expr ${#a[@]} - 1)]} && rm $a
2009-10-12 16:40:06
Functions: expr ls rm

plays with bash arrays. instead of storing the list of files in a temp file, this stores the list in ram, retrieves the last element in the array (the last html file), then removes it.

expr 512 \* 7
2009-09-23 19:11:38
User: chuckr
Functions: expr
Tags: math expr

expr will give you a quick way to do basic math from the CLI. Make sure you escape things like * and leave a space between operators and digits.

expr $(fdisk -s ` grep ' / ' /etc/mtab |cut -d " " -f1`) / 1024
while [ 0 ]; do expr 2365200000 \- `date +%s` \- `date --date "YYYY-mm-dd HH:MM:ss" +%s`; sleep 1; clear; done
2009-02-13 20:02:37
User: wwest4
Functions: expr sleep

watch the seconds of your life tick away - replace YYYY-mm-dd HH:MM:ss w/ your birthtime.